lingon
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Only 2.85 BogoMIPS

Fri Feb 13, 2015 8:00 pm

On a Raspberry Pi Model B I see only 2.85 BogoMIPS, which seems very strange as it is usually around 700 on the Raspberry Pi?

Code: Select all

uname -a
Linux rpicam2 3.18.7+ #755 PREEMPT Thu Feb 12 17:14:31 GMT 2015 armv6l GNU/Linux

Code: Select all

cat /proc/cpuinfo 
processor       : 0
model name      : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS        : 2.85
It even drops to 2:

Code: Select all

grep MIPS /proc/cpuinfo 
BogoMIPS        : 2.00

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DougieLawson
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Re: Only 2.85 BogoMIPS

Fri Feb 13, 2015 8:11 pm

Bogomips have been a useless thing for all the time that Linux has had them. They are deprecated and no longer used for any kind of kernel timing systems.

So rule #1 of bogomips is "Ignore them!".
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mikronauts
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Re: Only 2.85 BogoMIPS

Fri Feb 13, 2015 8:14 pm

About the only use I had for them was to get a rough indication of the clock speed of an unknown system. And that was iffy too.
DougieLawson wrote:Bogomips have been a useless thing for all the time that Linux has had them. They are deprecated and no longer used for any kind of kernel timing systems.

So rule #1 of bogomips is "Ignore them!".
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plugwash
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Re: Only 2.85 BogoMIPS

Fri Feb 13, 2015 8:25 pm

AIUI bogomips changed from their traditional definition of "the number of million times per second a processor can do absolutely nothing" to being related to some sort of timer resulting in much lower values.

http://en.wikipedia.org/wiki/BogoMips#T ... sed_delays

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DougieLawson
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Re: Only 2.85 BogoMIPS

Fri Feb 13, 2015 8:26 pm

The only reason why /proc/cpuinfo reports a bogus bogomips value is so that stupid programs that stupidly read it that for a value won't fail with "no value found" or "divide by zero". They'll get a syntactically valid, but physically invalid result.
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